optimise routes calculation and topology updates for fully connected mesh of node

local_peer.go

@@ -192,8 +192,9 @@ func (peer *localPeer) handleAddConnection(conn ourConnection, isRestartedPeer b
 	}
 
 	peer.router.Routes.recalculate()
-	peer.broadcastPeerUpdate(conn.Remote())
-
+	if !peer.isFullyConnectedTopology() {
+		peer.broadcastPeerUpdate(conn.Remote())
+	}
 	return nil
 }
 
@@ -209,7 +210,9 @@ func (peer *localPeer) handleConnectionEstablished(conn ourConnection) {
 	conn.logf("connection fully established")
 
 	peer.router.Routes.recalculate()
-	peer.broadcastPeerUpdate()
+	if !peer.isFullyConnectedTopology() {
+		peer.broadcastPeerUpdate(conn.Remote())
+	}
 }
 
 func (peer *localPeer) handleDeleteConnection(conn ourConnection) {
@@ -229,7 +232,9 @@ func (peer *localPeer) handleDeleteConnection(conn ourConnection) {
 	// update with unreachable peers (can cause looping)
 	peer.router.Peers.GarbageCollect()
 	peer.router.Routes.recalculate()
-	peer.broadcastPeerUpdate()
+	if !peer.isFullyConnectedTopology() {
+		peer.broadcastPeerUpdate(conn.Remote())
+	}
 }
 
 // helpers
@@ -294,3 +299,10 @@ func (peer *localPeer) setVersionBeyond(version uint64) bool {
 	}
 	return false
 }
+
+func (peer *localPeer) isFullyConnectedTopology() bool {
+	if peer.router != nil {
+		return peer.router.Config.SingleHopTopolgy
+	}
+	return false
+}

peer.go

@@ -86,7 +86,35 @@ func (peer *Peer) String() string {
 //
 // NB: This function should generally be invoked while holding a read lock on
 // Peers and LocalPeer.
-func (peer *Peer) routes(stopAt *Peer, establishedAndSymmetric bool) (bool, map[PeerName]PeerName) {
+func (peer *Peer) routes(stopAt *Peer, establishedAndSymmetric, fullyConnectedTopology bool) (bool, map[PeerName]PeerName) {
+	if fullyConnectedTopology {
+		return peer.routesForFullyConnectedTopology(stopAt, establishedAndSymmetric)
+	} else {
+		return peer.routesForGenericTopology(stopAt, establishedAndSymmetric)
+	}
+}
+
+// routesForFullyConnectedTopology calculates routes for a special case of network topology where each peer in the
+// mesh is fully connected to rest of the peers. So each peer is single hop and directly reachable from the peer.
+func (peer *Peer) routesForFullyConnectedTopology(stopAt *Peer, establishedAndSymmetric bool) (bool, map[PeerName]PeerName) {
+	routes := make(unicastRoutes)
+
+	for remoteName, conn := range peer.connections {
+		if establishedAndSymmetric && !conn.isEstablished() {
+			continue
+		}
+		remotePeer := conn.Remote()
+		if remotePeer == stopAt {
+			return true, routes
+		}
+		if remoteConn, found := remotePeer.connections[peer.Name]; !establishedAndSymmetric || (found && remoteConn.isEstablished()) {
+			routes[remoteName] = remoteName
+		}
+	}
+	return false, routes
+}
+
+func (peer *Peer) routesForGenericTopology(stopAt *Peer, establishedAndSymmetric bool) (bool, map[PeerName]PeerName) {
 	routes := make(unicastRoutes)
 	routes[peer.Name] = UnknownPeerName
 	nextWorklist := []*Peer{peer}

peers.go

@@ -416,7 +416,11 @@ func (peers *Peers) GarbageCollect() {
 
 func (peers *Peers) garbageCollect(pending *peersPendingNotifications) {
 	peers.ourself.RLock()
-	_, reached := peers.ourself.routes(nil, false)
+	singleHopTopology := false
+	if peers.ourself.router != nil {
+		singleHopTopology = peers.ourself.router.Config.SingleHopTopolgy
+	}
+	_, reached := peers.ourself.routes(nil, false, singleHopTopology)
 	peers.ourself.RUnlock()
 
 	for name, peer := range peers.byName {

router.go

@@ -37,6 +37,9 @@ type Config struct {
 	ProtocolMinVersion byte
 	PeerDiscovery      bool
 	TrustedSubnets     []*net.IPNet
+	// SingleHopTopolgy is used to indicate a topology of nodes participating
+	// in the mesh where each node is fully connected to other nodes
+	SingleHopTopolgy bool
 }
 
 // Router manages communication between this peer and the rest of the mesh.

routes.go

@@ -227,7 +227,11 @@ func (r *routes) calculate() {
 // to exchange knowledge of MAC addresses, nor any constraints on
 // the routes that we construct.
 func (r *routes) calculateUnicast(establishedAndSymmetric bool) unicastRoutes {
-	_, unicast := r.ourself.routes(nil, establishedAndSymmetric)
+	singleHopTopology := false
+	if r.ourself.router != nil {
+		singleHopTopology = r.ourself.router.Config.SingleHopTopolgy
+	}
+	_, unicast := r.ourself.routes(nil, establishedAndSymmetric, singleHopTopology)
 	return unicast
 }
 
@@ -255,7 +259,11 @@ func (r *routes) calculateBroadcast(name PeerName, establishedAndSymmetric bool)
 	if !found {
 		return hops
 	}
-	if found, reached := peer.routes(r.ourself.Peer, establishedAndSymmetric); found {
+	singleHopTopology := false
+	if r.ourself.router != nil {
+		singleHopTopology = r.ourself.router.Config.SingleHopTopolgy
+	}
+	if found, reached := peer.routes(r.ourself.Peer, establishedAndSymmetric, singleHopTopology); found {
 		r.ourself.forEachConnectedPeer(establishedAndSymmetric, reached,
 			func(remotePeer *Peer) { hops = append(hops, remotePeer.Name) })
 	}